Duchenne muscular dystrophy is caused by mutations in the dystrophin gene resulting in the loss of the dystrophin glycoprotein complex in skeletal muscle. Loss of dystrophin results in reduced sarcolemmal integrity, progressive muscle damage and compromised muscle function. There is currently no cure and limited treatment options for DMD and all affected children will die from this genetic disease unless new treatments are discovered soon. The ?7?1 integrin is major laminin receptor which can act as a surrogate for the dystrophin complex in skeletal muscle. Studies have demonstrated that enhanced transgenic expression of the ?7 integrin in skeletal muscle can improve muscle strength, function and longevity of mouse models of DMD. Together these studies indicate that drugs that target an increase ?7 integrin in skeletal muscle may serve as novel therapies for DMD. The Burkin laboratory has developed and used a muscle cell-based assay to identify small molecules that increase the ?7 integrin in skeletal muscle. Strykagen Corp. has the option to license Stryka-969, the top hit compound identified from this screen. In this Phase I STTR application we will screen Stryka-969 compound analogs using the muscle cell based assay and develop structure activity relationships (SAR), perform medicinal chemistry and identify lead compounds with optimal activity that target the ?7 integrin in mouse and human myogenic cells for further development. Second we will confirm on-target and off- target activity of each lead compound in human DMD myogenic cells. This proposal will translate exciting studies in transgenic mice into the development of a new line of ?7 integrin-targeted therapeutics for the treatment of DMD.